1. Field of the Invention
The described technology relates to a developing device used in an image forming device such as a copying machine, a printer, and a facsimile machine employing an electro-photographic system, and relates to an image forming device.
2. Description of Related Art
FIG. 1 is a sectional view showing the configuration of a conventional developing device. The developing device used in an image forming device such as a copying machine employing an electro-photographic system comprises: a case 104 for storing binary developer; a stirring roller 105 for stirring the developer inside the case 104; a developing roller 101 for transferring the developer to an electrostatic latent image; a control member 102 for controlling the amount of developer transferred to the electrostatic latent image; and a reflux plate 103 for flowing back excess developer controlled by the control member 102 to the stirring roller 105 (see, for example, Japanese Patent Application Laid-Open No. 1-237577 (1989)). Another developing device using binary developer is also known in which a folded piece is provided at an end portion on a control member side of a reflux plate for flowing back excess developer controlled by the control member to a stirring roller (see, for example, Japanese Patent Application Laid-Open No. 3-89273 (1991)).
The developing roller 101 comprises: a non-rotary magnet roller 100 provided with magnetic N-poles and magnetic S-poles disposed alternately at a plurality of positions in the circumferential direction; and a nonmagnetic sleeve 106 fitted to the outside of the magnet roller 100 in a freely rotatable manner. One end portion of the reflux plate 103 is disposed in the vicinity of the outer periphery of the stirring roller 105, while the opposite side of said one end portion is disposed in the vicinity of the outer periphery of the developing roller 101. The control member 102 is disposed in the vicinity of the outer periphery of the developing roller 101 in the downstream side (left-hand side in the figure) of the transfer direction relative to the opposite side of said one end portion of the reflux plate 103.
In the developing device constructed as described above, carrier (magnetic powder) and toner of the binary developer stored in the case 104 are stirred by rotation (in the counterclockwise direction in the figure) of the stirring roller 105, and the toner adheres to the periphery surface of the carrier. Further, when the sleeve 106 of the developing roller 101 rotates (counterclockwise in the figure), the developer is transferred toward a gap between the developing roller 101 and the control member 102, so that the transferring amount to the electrostatic latent image is controlled by the control member 102. The developer having passed through the gap is transferred to the electrostatic latent image, while excess developer resulting from control by the control member 102 stagnates in the space between the control member 102 and the reflux plate 103. When the stagnated amount increases, the developer is flowed toward the reflux plate 103, then guided by the reflux plate 103, and thereby flowed back to the stirring roller 105.
As described above, the developer circulates inside the case 104 via the control member 102, the reflux plate 103, and the like. Nevertheless, for example, when the developer deposits on the reflux plate 103 so that the reflux of the developer is blocked, a problem arises that smooth circulation of the developer is prevented. When smooth circulation of the developer is prevented, adverse influences are caused such as unstable image quality.